Portable hydraulic motor-operated ratchet wrench



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Feb- 22, 1955 R. E. WALLACE, sR

PORTABLE HYDRAULIC MOTOR-OPERATED RATCHET WRENCH Filed July 18, 1952Feb. 22, 1955 R. E. WALLACE, sR

PORTABLE HYDRAULIC MOTOR-OPERATED RATCHET WRENCH Filed July 18, 1952 2Sheets-Sheet 2 United States Patent O PORTABLE HYDRAULIC MOTOR-OPERATEDRATCHET WRENCH Robert E. Wallace, Sr., Smithfield, Ohio Application July18, 1952, Serial No. 299,552

11 Claims. (Cl. 81-58.1)

This invention relates as indicated, to a portable hydraulic ratchetwrench, and, more particularly, to an improved arrangement of ratchetwrench mechanism having a self-contained and manually operable hydraulicsystem which may be selectively operated through its hydraulic operatingmechanism or in the mechanical fashion of a conventional ratchet wrench.

In many instances, nuts become locked or frozen on their bolts so thatit is ditlicult to begin rotation of the nut to effect its removal. Thisdifficulty is particularly common in the case of nuts of large size suchas those used on locomotive main and side rods, large electricgenerators and motors, rolling mill housings, etc. Such nuts arefrequently located in a position in which it is impossible to use awrench having a handle sufciently long to obtain the leverage necessaryto start the desired loosening motion. This large leverage is requiredonly during initial loosening movement since a considerably smallerleverage is effective to continue rotation of the nut once such rotationhas been initiated.

One of the objects of this invention is to provide a Wrench in which anextremely large mechanical advantage may be obtained for eecting initialor nal nut rotation without the necessity of providing an unduly longwrench handle. To this end, the invention contemplates the provision ofa ratchet wrench having relatively rotatable operating parts. One ofsuch parts is arranged for actuation by a piston having an hydraulicoperating system. The hydraulic system is self-contained and mounted asa unit on the wrench and includes a manually operable pump which is sodesigned that it must be actuated many times to move the actuatingpiston a distance suicient to rotate the wrench actuating part connectedthereto through an angle equivalent to one or two of the ratchet cogs.In this manner, a Very high mechanical advantage is obtained forinitiating or concluding rotational movement of the nut.

A further object of the invention is to provide an hydraulic system ofthe character described in which the ratchet operating piston isautomatically returned to a starting position after movement through aWork stroke of predetermined length so that it will be reciprocatedcontinuously and thereby effect a continuous rotation of the wrenchoperating parts in response to continuous manual operation of the handpump.

Other objects and advantages of the invention will become apparent fromthe following description.

In the drawings there is shown a preferred embodiment of the invention.In this showing:

Fig. l is a plan view of a ratchet wrench, a portion of the handlethereof being shown broken away, and having applied thereto an hydraulicoperating system constructed in accordance with the principles of thisinvention;

F Fig. 2 is an elevational View of the wrench shown in ig. l;

Fig. 3 is a sectional view taken substantially along the line III--IIIof Fig. 2;

Fig. 4 is a fragmentary perspective view of the nut ocket actuatingspindle and of an actuating pawl there- Fig. is a fragmentary anddiagrammatic showing, parts thereof being illustrated in section, of thehydraulic system shown in Figs. 1 and 2; and

Fig. 6 is a sectional view taken substantially along the line VI--VI ofFig. 5.

Referring rst to Figs. 1 and 2, the numeral 1 designates as a whole aratchet Wrench comprising a housing 2 in which there is mounted aratchet mechanism of a character to be described and having an operatinghandle 3 connected thereto. Actuating studs 4 project from oppositesides of the housing 2 for engagement with nut sockets in a conventionalfashion. The actuating studs 4 are each provided with spring biasedpawls or detents 5 for holding sockets in position thereon in aconventional manner.

As best shown in Figs. 4 and 5, the square studs 4 are formed on theaxial ends of a rotatable operating member 6 which is rotatably mountedcentrally of the housing 2. The operating member 6 is provided with apair of slots 7 respectively extending inwardly from the peripherythereof and having a pair of pin-receiving openings 8 at their innerends. Detents or pawls 9 are mounted for sliding rectilinear movement inthe slots 7, and have a pair of pins 10 at their inner ends which arereceivable in the openings 8. Springs 11 are receivable in the openings8 and when compressed by the ends of the pins 10 provide a bias formoving the pawls outwardly in the slots 7. The outer ends of the pawls 9have locking teeth 14 thereon for meshing engagement with similarratchet teeth 15 on the inner surface of an annular actuating member 16(see Fig. 5 which is rotatably mounted in the housing 2. As will beapparent from the showing of Fig. 5, the teeth 14 and 15 do not extendradially of the rotating operating parts 6 and 16 but are inclined withrespect to the radii thereof in such manner that rotation of the annularoperating member 16 in a clockwise direction as viewed in Fig. 5 willcam the pawls 9 inwardly and move the ratchet teeth 14 and 15 out ofmeshing engagement. This camming movement of the pawls 9 is inwardlyagainst the action of their biasing springs 11. Upon movement of therotatable actuating member 16 in a counterclockwise direction, the slopeof the engaging surfaces on the teeth 14 and 15 produces a reactiveforce which holds such teeth in meshing engagement, and thus locks thepawls 9 to the annular operating part 16 for rotation therewith tothereby impart rotation to the spindle 6 and the socket actuating studs4 connected thereto. The annular operating part 16 has an actuating lug17 projecting laterally therefrom into an opening 18 in the housing 2 inwhich it has an oscillating movement. A spring 19 has engagement betweenthe housing 2 and lug 17 for resiliently biasing the oscillatingmovement of the annular operating part 16 in a clockwise direction.

The actuating lug 17 is provided with a pivot pin receiving openingparallel to the axis of the rotatable operating parts 6 and 16 and inwhich a pivot pin 20 (see Fig. 6) is mounted. A motion transmittingmember 21 is journaled on the pin 20 and has a universal connection 22with a piston 23 which is slidable in a cylinder 24 so thatreciprocating movement of the piston 23 will be effective to impart anarcuate movement to the actuating lug 17. Admission of hydraulic fluidunder pressure to the space 25 within cylinder 24 moves the piston 23 torock the lug 17 against the action of its biasing spring 19. The spring19 through the lug 17V and piston 23 is eifective to force fluid out ofthe space 25 in a manner to be described.

Fluid pressure for actuating the piston 23 is supplied by a pump 26. Thepump 26 comprises a cylinder 27 having a piston 28 reciprocable therein.On the down stroke of the piston 28 as viewed in Fig. 5, a ball checkvalve 29 is unseated and fluid under pressure is delivered to theconduit 30, and through valve port 31, passage-way 32, and opening 33 tothe cylinder chamber 25. On the up stroke of the piston 28, the ballcheck valve 29 seats to disconnect the cylinder 27 from the highpressure conduit 30, and the ball check valve 34 is unseated to connectthe cylinder 27 with the low pressure conduit 35. The low pressureconduit 35 has a connection 36 to a reservoir 37 of hydraulic fluid. Theup stroke of the piston 28 is thus operative to draw a charge ofhydraulic iuid into the cylinder 27.

The low pressure conduit 35 has a branch 38 by which it is connectableto the conduit 32 through a port in the wall of the passage-way 32 whichis opened and closed by a valve 39. Opening and closing of the valve 39is eifected by an operating stem 40 having a slotted actuating link 41at an opposite end thereof. An actuating pin 42 secured to the lug 17projects through the slot in the link 41. Upon arcuate movement of theactuating lug 17 to the right as viewed in Fig. 5, the pin 42 will moveto the end of the slot in the link 41, and drag the valve actuating stem40 to the right to open the valve 39 and thereby connect low pressureconduits 36 and 38 to the passageway 32. In this manner, the pressure ofthe fluid in the passageway 32 is released, and fluid is exhausted fromthe cylinder chamber 25 to the reservoir 37 by operation of the spring19 in moving the lug 17 to the left as viewed in Fig. 5. In a manner tobe described, the fluid in the reservoir 37 is maintained under aminimum pressure and exhaust of iluid through conduit 38 is against thisminimum pressure. This minimum exhaust pressure reacts against the valve39 and is eiective to hold the valve 39 in its open position until suchtime as itis seated by operation of the actuating pin 42. This seatingaction takes place when the pin 42 moves to the left end of the slot inthe link 41 in the position illustrated in Fig. 5. The stern 40 isprovided with a resilient connection 44 intermediate its ends to allowfor over travel movement thereof by its actuating link 41 and the pin42.

A safety valve 46 is provided for limiting the torque which can beapplied by the hydraulic system to the operating member 16. The valve 46is shown in its closed position and is provided with a spring 47 biasingit to such position. The biasing spring 47 has one end bearing againstthe valve 46 and its other end bearing against an adjustable collar 48.The collar 48 is threaded on the shank of a stem which can be manuallyrotated to adjust the axial position of the collar 48 thereon andthereby the force of the spring holding the valve 46 in closed position.An arm 50 on the collar 48 may be utilized to indicate the position ofthe collar 48 with respect to the stem 49, and indicia calibrated inpounds torque or pressure may be provided to indicate the pressure whichwill be required to unseat and open the valve 46. When this pressure isexceeded, the valve 46 will open and connect the passage-way 32 to theexhaust conduit 38 and therebv relieve the pressure in the cylinder 25.

The reservoir 37 comprises a cylinder 51 having a piston 52 mounted inthe upper end of the fluid chamber therein. The piston 52 has a spring54 biasing it downwardly to maintain a minimum pressure on the fluid inthe chamber 53. To facilitate assembly of the piston 52 in the cylinder51, a cylinder 55 having an inturned lip 56 at the upper end thereof isconnected to the piston 52. An extension 57 has a detachable threadedconnection at its lower end to the cylinder 51, and its upper end has aclosure in which is formed a pair of slots S8 through which a pair ofactuating members 59 project. The lower ends of the members 59 haveoutwardly proiecting lugs 60 for a purpose to be described. The parts 59and 60 are connected with slides 61 having sliding engagement on theupper closed end of the cylinder 57. Pins 62 project upwardly from theslides 61 and engage in arcuate slots 63 formed on a cap 64 as bestshown in Fig. 2. The can 64 has a pair of manually engageable lugs 65 bywhich it mav be rotated on the cylinder 57. Prior to assembling of thecylinder 57 on the cylinder 51, the cap 64 is rotated to move the lugs60 to their innermost positions. In this position of the lugs 60. thepiston 52 may be moved upwardly with respect to the cylinder 57, the lip56 clearing the lugs 60. When the lip 56 is moved to its uppermostposition against the upper end of the cvlinder 57, the cao 64 is rotatedto move the members 59 radially outwardly in the slots 58 so that thelugs 60 will engage under the lip 56 and prevent downward movement ofthe cvlinder 55 bv the spring 54 with respect to the cylinder 57. Thecvlinder 57 may then be threaded into position on the cylinder 51 afterwhich the cap 64 is turned to move the lugs 60 inwardly to a position inwhich they clear the lip 56 and release the piston 52 for a downwardmovement by its biasing spring 54. The piston 52 will then movedownwardly until it engages with the upper surface of the hydraulic uidin the chamber 53 in which position its spring 54 will be effective tomaintain the uid in the chamber 53 under pressure.

In the event that the hydraulic system is not to be employed, a latch 67is provided for locking the lug 17 against return movement by itsbiasing spring 19. The latch 67 comprises a detent 68 having a springfor moving it upwardly with respect to the housing 2 as viewed in Fig.to a position in which it will lie in the path of movement of a lockingmember 69 carried by the lug.

With the detent 68 in its upper position, the locking member 69 willprevent operation of the wrench by its hydraulic system. The detent 68is provided with an operating handle which projects outwardly through aninverted L-shaped slot (not illustrated) by which the detent operatinghandle and the detent 68 may be held in their upper locking position.

In order to effect an hydraulic operation of the wrench, the latch 68 isplaced in its lower position as illustrated in Fig. 5, and for suchoperation, the conduit 30 may be considered as being directly connectedto the passageway 32 through the port 31. Upon manual operation of thepiston 28, iluid pressure will be pumped through the conduit 30 to thepressure chamber 25 to eiect a movement of the piston 23 to the right asviewed in Fig. 5. Movement of the piston to the right will actuate theoperating lug 17 through the motion transmitting member 21. Thismovement will continue until the pin 42 moves to the end of the slot inthe link 41 to unseat the exhaust valve 39. When the exhaust valve 39 isunseated, uid in the chamber 25 will be exhausted through the conduits38 and 36 to the reservoir 37, and the spring 19 will be effective toreturn lug 17 to its initial position as shown in Fig. 5. As lug 17moves to this position, the pin 42 will move to the left end of the slotin the link 41 and seat the valve 39 to thereby disconnect the chamber25 with respect to the exhaust conduit 38. The hydraulic system willthen be again in a position to eiTect another actuation of the lug 17through another small angular movement.

It is, of course, to be understood that when the lug 17 is actuated bythe piston 23, the annular member 16, through the locking detents 9 willrotate the spindle 6 and thus apply torque to the nut socket which maybe mounted on the studs 4. Upon return movement of the lug 17 by thespring 19, the slope of the meshing teeth 14 and 15 is such that thepawls 9 will be cammed inwardly to allow rotational movement of annularmember 16 without a similar movement being imparted to the spindle 6.

Attention is directed to the fact that a single reciprocating movementof the piston 23 is effective only to move the operating member 16through a relatively small angle, and that the volume of fluid displacedby the pump piston 28 during one working stroke thereof is relativelysmall as compared to the volume of fluid required to effect a Workingstroke of the piston 23. For this reason, a large number of strokes willbe required of the piston 28 to effect a single stroke of the piston 23and a resultant movement of the wrench operating member 16 through asmall angular distance. In this manner, a large mechanical advantage isobtained, and a large operating torque may be applied to a nut throughthe application of relatively small increments of force to the manuallyoperated piston 28.

The hydraulic system described above is adapted for operation from asource of uid pressure supply in which the uid pressure is created by amotor-driven pump rather than a manual system as described above. Forthis purpose, a pair of two-way valves 71 and 72 are respectivelymounted in the conduits 30 and 35 for disconnecting the reservoir 37with respect to the exhaust conduit 38 and for disconnecting the conduit30 with respect to the manual pump 26. Upon disconnecting operation ofthe valves 71 and 72 in this manner, the conduit 30 will be connected toa uid pressure supply conduit 73 and the exhaust conduit 38 will beconnected to an exhaust conduit 74, the conduit 73 being connected witha uid pressure supply source (not shown). It will be noted that theexhaust conduit 74 is provided with a spring-biased ball-check valvewhich maintains a minimum exhaust pressure for holding the valve 39 inits open position as described above in connection with the pressure ofthe reservoir 37. The ball-check valve in exhaust passage 74 performsthe same function as spring 54 in the reservoir.

To control the connection of cylinder space 25 to the pressure supplyconduit 73, a valve 76 controlling the opening and closing of the port31 is provided. The valve 76 is operated by a stem 109 having its innerend connected with the valve 76 and positioned in a pressure chamber 77which is connected with the high pressure conduit 30. The outer end ofthe stem 109 has a rectilinear sliding movement through a stuffing box110 and projects into a chamber 78 which is at atmospheric pressure, itbeing ported to the atmosphere as at 111. A spring 112 provides a biasagainst the outer end of the stem 109 for moving the valve 76 to itsclosed position. The spring 112 has a force which is just su'licient toclose the valve 76 against the force of the minimum exhaust pressure inthe passage 32 as controlled by either the ballcheck valve 74 or thespring 54. Any time this pressure is exceeded, as will happen when valve39 closes and pressure fluid is admitted to passage 32, the valve 76will move to the left, as viewed in Fig. 5, against the action of thespring 112 and open the port 31 to connect the cylinder 25 with thefluid supply conduit 30.

To provide for initial opening of the port 31 for supplying pressure tothe passage 32 which will be eiective to open valve 76, an operating pin79 is secured to the piston 23. The pin 79 has a length such that itengages with and unseats the valve 76 when the piston 23 is moved to itsfully retracted position by the spring 19 as illustrated in Fig. 5. Inoperation, when the piston 23 moves to its retracted position, the pin42 closes the exhaust valve 39, and the pin 79 strikes the valve 76 andunseats it, allowing fluid pressure to enter passage 32. This pressureacting on the right end of valve 76, as viewed in Fig. 5, forces it tothe left, thereby completing its movement to a fully open positionconnecting the cylinder pressure chamber 25 to the fluid pressure supplyconduit 73. The fluid pressure admitted to the chamber 25 will move thepiston 23 to the right to supply torque through the ratchet mechanism tothe wrench. As the piston 23 moves to the right, the pressure of thefluid in the chamber 77 and passage 32 will be effective to maintainvalve 76 in its open position. When the piston 23 moves to the end ofits working stroke, the pin 42 will open the valve 39 and therebyconnect the chamber 25 to the exhaust conduit 74. Opening of valve 39releases the pressure in passage 32, and the spring 112, together withthe iluid pressure exerted on the exposed area on the left end of valve76, as viewed in Fig. 5, move valve 76 to closed position. Also, spring19 starts return movement of piston 23 and fluid will be exhausted fromcylinder chamber 25. At near the end of the return movement, pin 42operates to move valve 39 to its closed position to disconnect chamber25 from exhaust. Closure of exhaust valve 39 takes place just at, orjust prior to, the time initial contact of pin 79 with valve 76 takesplace.

In order that the final movement of the piston 23 to the left as viewedin Fig. 5 may take place for the purpose of unseating the valve 76, anexpansible chamber 81 is provided. The chamber 81 is cylindrical inshape and has a piston 82 having a spring 83 biasing it to the right asviewed in Fig. 5, the chamber in which the piston 82 is mounted beingported at the left of the piston, as viewed in Fig. 5, to theatmosphere. The spring 83 exerts a force sufficient to move the piston82 to the right as viewed in Fig. 5 only when the pressure in thepassage 32 is at the exhaust pressure determined by the check valve in74 or the spring 54 in reservoir 37. At all higher pressures, the piston82 moves to the left to the position illustrated. Final movement of thepiston 23 to the left by the spring 19 for opening the valve 76increases the pressure in the passage 32. This increased pressure reactsagainst the piston 82 which will move outwardly against the action ofits biasing spring 83 to allow additional fluid to escape from thechamber 25 after closure of the exhaust valve 39, and thereby enablefinal movement of the piston 23 to the left as viewed in Fig. 5 to openthe valve 76 so that another operating cycle of the piston 23 may bestarted. Except for the action of the piston 82 in accommodatingmovement of fluid during final movement of the piston 23 after closureof exhaust valve 39, the lluid in passage 32 would lock the pistonagainst movement to its fully retracted position. In this manner, thepiston 23 will be reciprocated continuously to effect continuousoperation of the wrench ratchet mechanism as long as the fluid conduits73 and 74 are connected with the chamber 25 through the valves 71 and72.

Referring again to Fig. l, it will be noted that the reservoir 37 ismounted by a bracket 85 on a supporting bracket 86. In a similar manner,the pump 26 is connected by a bracket 87 to the supporting bracket 86.The operating mechanism for the pump ,26 includes a stationary hand grip88 secured to the bracket 86 and an overlying hand grip 89 having apivotal connection 90 at one end thereof to the upper end of a togglelink 91, the lower end of which is pivoted at 92 to the supportingbracket 86. Spaced from pivot 90, a second pivot 93 connects the lever89 to the upper end 94 of the piston 28. Intermediate the pivotalconnections and 93 the manually operative lever 89 has a pivotalconnection to a cap 95 which bears against the upper end of a biasingspring 96, the lower end of the spring 96 bearing against a stationarymember 97 on the supporting bracket 86. A locking link 98 is providedfor tying the outer ends of the levers 88 and 89 together and to preventupward movement of the lever 89 by its spring 96. When the link 98 isrotated to release the lever 89, its spring 96 moves it upwardly toeffect a suction stroke of the piston 28. Thereafter, the levers 88 and89 may be squeezed Atogether by one hand of an operator to effect apressure stroke of the piston 28.

As best shown in Figs. 2 and 3, the bracket 86 is mounted on the handle3 by supporting brackets 101 which have a polygonal shape similar tothat of the handle 3. Adjacent the brackets 101 the handle 3 is providedwith a pair of spaced circular portions 102 of reduced area. In theevent that it is desired to change the angular position of the Huidsystem relative to the handle 3 it is only necessary to move the bracket86 lengthwise on the handle until it is opposite the circular positions102. The bracket 86 may then be rotated to the desired angular positionand then moved endwise relative to handle portions 102 so that thepolygonal contour of the outer surfaces of the handle 3 and the similarcontour of the inner surfaces of the brackets 101 will be effective toprevent turning movement of the supporting bracket 86 on the handle 3. Aball detent 103 is provided in the handle 3 for releasable holdingengagement with one of the supporting brackets 101 when the brackets 101are moved to a position over the polygonal surface of the handle 3. Thedetent 103 is for the purpose of releasably holding the bracket 86against axial shifting movement on the handle 3. In order that thisrelative rotational movement of the bracket 86 and the handle 3 can beeffected without interference, the uid supply conduits 30 and 35 areprovided with flexible portions 35a 'and 30a respectively.

While the apparatus described above and shown inthe drawings representsa preferred embodiment of the invention, it will be understood that thisis merely by way of illustration, and that various changes may be madetherein Within the contemplation of this invention and under the scopeof the following claims.

I claim:

l. The combination with a ratchet wrench having a nut socket receivingspindle, a handle, and ratchet mechanism including a rotatable ratchetmember interconnecting said handle and spindle, of a fluid pressuremotor having a reciprocable piston, means connected with said piston andmember for oscillating said member in one rotational direction inresponse to the power stroke of said piston, a spring biasing saidmember and thereby said piston for lmovement in an opposite direction inresponse to the exhaust stroke of said piston, and valve meansresponsive to movement of said piston to the end of its power stroke forconnecting said motor to an exhaust for the exhaust stroke of saidpiston.

2. The. combination with a ratchet wrench having a nut socket receivingspindle, a handle, and ratchet mechanism including a rotatable ratchetmember interconnecting said handle and spindle, of a uid pressure motorhaving a reciprocable piston, means connected with said piston andmember for oscillating said member in response "to reciprocation of saidpiston, a self-contained hydraulic system including a manually operablepump for supplying iiuid pressure to said motor, and bracket meansmounting said pump on said handle.

3. The combination with a ratchet wrench having a nut socket receivingspindle, a handle, and ratchet mechanism including a rotatable ratchetmember interconnecting said handle and spindle, of a uid pressure motorhaving a reciprocable piston, means connected with said piston andmember for oscillating said member in response to reciprocation of saidpiston, a selfcontained hydraulic system including a manually operablepump for supplying iluid pressure to said motor, and a reservoir havingvalve means operable to connect it alternately to said pump and to saidmotor, and

bracket means mounting said pump and reservoir on said handle.

4. The combination with a ratchet wrench having a nut socket receivingspindle, a handle, and ratchet mechanism including a rotatable ratchetmember interconnecting said handle and spindle, of a Huid pressure motorhaving a reciprocable piston, means connected with said piston andmember for oscillating said member in one rotational direction inresponse to the power stroke of said piston, a spring biasing saidmember and thereby said piston for movement in an opposite direction inresponse to the exhaust stroke of said piston, valve means responsive tomovement of said piston to the end of its power stroke for connectingsaid motor to an exhaust for the exhaust stroke of said piston, and amanually operable pump for supplying uid pressure to said motor.

5. The combination with a ratchet wrench having a nut socket receivingspindle, a handle, and ratchet mechanism including a rotatable ratchetmember interconnecting said handle and spindle, of a fluid pressuremotor having a reciprocable piston, means connected with said piston andmember for oscillating said member in one rotational direction inresponse to the power stroke of said piston, a spring biasing saidmember and thereby said piston for movement in an opposite direction inresponse to the exhaust stroke of said piston, an exhaust valve for saidmotor, and means interconnecting said valve and rotatable ratchet memberfor closing said exhaust valve at one end of oscillating movement ofsaid member and for opening said exhaust valve at the other end ofoscillating movement of said member.

6. The combination with a ratchet wrench having a nut socket receivingspindle, a handle, and ratchet mechanism including a rotatable ratchetmember interconnecting said handle and spindle, of a fluid pressuremotor having a reciprocable piston, means connected with said piston andmember for oscillating said member in one rotational direction inresponse to the power stroke of said piston, a spring biasing saidmember and thereby said piston for movement in an opposite direction inresponse to the exhaust stroke of said piston, an exhaust valve for saidmotor, means interconnecting said valve and rotatable ratchet member forclosing said exhaust valve at one end of oscillating movement of saidmember and for opening said exhaust valve at the other end ofoscillating movement of said member, a fluid pressure supply conduit, acontrol valve controlling the connection of said conduit with saidmotor, and means responsive to opening of said exhaust valve for closingsaid control valve.

7. The invention defined in claim 6 characterized by said last namedmeans including a pressure chamber, an operating stem for said controlvalve having a portion thereof positioned in said chamber, a stuilingbox through which the outer end of said stem extends and is slidable,the outer end of said stem being subjected to atmospheric pressure, anda spring acting on the outer end of said stern and biasing said controlvalve to its closed position.

8. The combination with a ratchet Wrench having a nut socket receivingspindle, a handle, and ratchet mechanism including a rotatable ratchetmember interconnecting said handle and spindle, of a uid pressure motorhaving a reciprocable piston, means connected with said piston andmember for oscillating said member in one rotational direction inresponse to the power stroke of said piston, a spring biasing saidmember and thereby said piston for movement in an opposite direction inresponse to the exhaust stroke of said piston, an exhaust valve for saidmotor, means interconnecting said valve and rotatable ratchet member forclosing said exhaust valve at one end of oscillating movement of saidmember and for opening said exhaust valve at the other end ofoscillating movement of said member, a iluid pressure supply conduit, acontrol valve controlling the connection of said conduit with saidmotor, means responsive to opening of said exhaust valve for closingsaid control valve, and means connected to one of the operating parts ofsaid system for opening said control valve subsequent to closure of saidexhaust valve.

9. The invention dened in claim 8 characterized by said last named meanscomprising an actuating pin connected to said piston.

10. The combination with a ratchet wrench having a nut socket receivingspindle, a handle, and ratchet mechanism including a rotatable ratchetmember interconnecting said handle and spindle, of a iiuid pressuremotor having a reciprocable piston, means connected with said piston andmember for oscillating said member in one rotational direction inresponse to the power stroke of said piston, a spring biasing saidmember and thereby said piston for movement in an opposite direction inresponse to the exhaust stroke of said piston, an exhaust valve for saidmotor, an operating stern having a connection at one end to said valveand a slot at its other end, and an operating pin connected to saidmember for oscillation therewith and projecting through said slot foractuating said stem to close said valve at one limit of oscillationthereof and to open said valve at the other limit of oscillationthereof.

1l. The combination with a ratchet wrench having a nut socket receivingspindle, a handle, and ratchet mechanism including a rotatable ratchetmember interconnecting said handle and spindle, of a fluid pressuremotor having a reciprocable piston, means connected with said piston andmember for oscillating said member in one rotational direction inresponse to the power stroke of said piston, a spring biasing saidmember and thereby said piston for movement in an opposite direction inresponse to the exhaust stroke of said piston, valve means responsive tomovement of said piston to the end of its power stroke for connectingsaid motor to an exhaust for the exhaust stroke of said piston, and aspring-biased valve for limiting the pressure within said motor actingagainst said piston.

References Cited in the tile of this patent UNITED STATES PATENTS1,812,816 Weaver June 30, 1931 2,112,693 Douglass Mar. 29, 19382,508,568 Ellison May 23, 1950

